1. Field of the Invention
The present invention relates to a dye-containing negative working curable composition constituting a color filter used for liquid crystal display elements and solid state image pick-up elements and suitable for forming colored images, as well as to a color filter using the dye-containing curable composition and a method of producing the same.
2. Description of the Related Art
As processes for preparing a color filter used for liquid crystal display elements (LCD) and solid state image pick-up elements (CCD, CMOS and the like), a staining process, a printing process, an electrodeposition process and a pigment dispersion process are known.
In the pigment dispersion process, the color filter is prepared by a photolithographic process using a colored radiation-sensitive composition prepared by dispersing a pigment in a photosensitive composition. The color filter prepared by this process is stable with respect to light, heat and the like since pigments are used. A sufficient degree of positional accuracy can be obtained in this process since the colored radiation-sensitive composition is patterned by the photolithographic process, and this process has been widely used as a process suitable for preparing the color filter for a large screen and high accuracy color display.
In preparing a color filter by the pigment dispersion process, the radiation-sensitive composition is first coated on a glass substrate with a spin coater or a roll coater and dried to form a coating film. Then, colored pixels are obtained by patterned-exposure and development of the coating film. The color filter can be prepared by repeating this operation a number of times corresponding to the number of hues.
As the pigment dispersion process, a negative photosensitive composition in which photopolymerizable monomer and photopolymerization initiator are combined with alkali soluble resin is described (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 2-199403).
On the other hand, recently, in the color filter for solid state image pick-up elements, even higher resolution is desired, but the conventional pigment dispersions have difficulties in further improving the resolution. Because of the problem such as generation of color irregularities due to coarse particles of the pigment, it is not suitable for the use which requires fine patterns such as solid state image pick-up elements.
In view of the problem, technologies in which dyes are used instead of pigments have been proposed. However, photosensitive compositions containing dyes are generally lower in sensitivity as compared with pigment containing systems. In response to this problem, methods in which no alkali-soluble resins are added are known (see, for example, WO 2005-083521).
Further, methods of adding compounds having a hydroxyl group within a molecule to negative working curing systems using organic solvent-soluble dyes, to thereby reduce contamination generation over time are known (see, for example, JP-A-2005-227722).